11 Dec 20

How Porsche squeezes maximum performance and efficiency out of its powertrain

The ABB FIA Formula E World Championship requires teams and drivers to walk the tightrope, balancing the need to lap as quickly as possible over a race distance whilst constantly managing available energy.

Race engineers and drivers combine to squeeze every last bit of usable energy out of their cars’ batteries – down to the final tenth of a percent come the chequered flag. Away from the circuit, thousands of hours’ groundwork goes into perfecting efficiencies within the cars’ mechanics and software over the course of a season.

Powertrain efficiency and drive performance go hand in hand, and the team that has the best handle on this trade-off gives itself, and its drivers, the best possible chance of the top step of the podium, with the margins between Formula E’s 12 teams – 10 of which are manufacturer outfits – and 24 world-class drivers finer than ever.

Fractions of a percent

Porsche Motorsports, which runs the TAG Heuer Porsche Formula E Team, has enlisted the help of Ansys simulation engineers to employ its expertise in getting the absolute maximum out of all of the key elements that make up a Gen2 Formula E powertrain – all in a bid to give Andre Lotterer and Pascal Wehrlein the jump on the rest.

The battery, inverter, regen characteristics and motor are all at play, and perfecting the interaction between those components in combination with the mechanics of the car and its controls, are the key to mastering the fine margins.

“Fully electric racing is about efficiency,” says TAG Heuer Porsche’s Head of Operations Amiel Lindesay. “We have a defined battery capacity and power output given to us by Formula E which is the same for everybody. It’s up to us to be as efficient as possible to go that little bit faster compared to the competition.

“We’re left to optimize the powertrains; everything that comes downstream of the battery and inverter, e-machine gearbox and driveshafts. The ultimate goal is to make these components as efficient as possible.

“Energy management is a huge task, of course, and then managing all the regeneration phase, basically managing the brakes – both the hydraulic and electric motor braking together.”

 

Ansys’ engineers work hand in hand with the Porsche Motorsport engineers to identify where improvements can be made. Given fractions of a second per lap over the course of the race are enough to fire a car from the ultra-competitive mid-pack onto the podium, pinpointing even the most marginal of gains is vital.

This could mean tweaks that keep the powertrain at its optimal temperature, for example, or reworking the way the software controls energy utilization. In either case, the team that finds these slivers of performance and efficiency is the one that can provide its drivers with the edge they need to make that last lap move or hold on to vital points under pressure.

Getting technical

The confines the teams are given to work within by the FIA and Formula E in developing their cars are tight, so any simulation or modelling has to be error-free and extremely accurate.

Hundreds of thousands of eventualities, variables and changes to components and their settings are analyzed by the team, with Ansys employing reduced order models and models of optimal prognosis in its simulations – allowing for high accuracy and sensitivity, fast simulation speed and definitive analysis. The company’s physics-based simulations are then run to double down on accuracy.

“The simulation tools that Ansys can provide us in terms of optimizing efficiency and functionality of electric drivetrains is just superior to everything else we could see in the market,” says Malte Huneke, Technical Project Leader for Porsche’s Formula E operations.

“We used Ansys Maxwell for detailed e-machine optimization and then also Ansys Twin Builder to optimize the control algorithms between inverter, e-machine and also the battery.”

“E-mobility is really important for Porsche,” adds Head of Factory Motorsport at Porsche, Pascal Zurlinden. “It's part of our Sustainability Program and motorsport, via Formula E, is our laboratory for all the e-mobility technology. Using Ansys for simulation allows our engineers to go much quicker to the best solution.”

How Porsche and Ansys squeeze every tenth of a second out of their Formula E car